WASHINGTON (AP) — The Federal Aviation Administration announced Wednesday that it will reduce air traffic by 10% across 40 high-volume markets beginning Friday morning to maintain safety during the ongoing government shutdown. The reduction stands to impact thousands of flights nationwide.

The FAA is confronting staffing shortages among air traffic controllers who have been working unpaid since the shutdown began on October 1. Many controllers have been calling out of work, resulting in delays across the country.

FAA Administrator Bryan Bedford stated, We can’t ignore it, when addressing the growing staffing pressures caused by the shutdown. He and Transportation Secretary Sean Duffy plan to meet with airline executives later Wednesday to discuss how to safely implement the reduction in flights.

The early indicators are telling us we can take action today to prevent things from deteriorating, Bedford added.

While specific markets affected by the reduction will not be disclosed until after discussions with airline executives, a list will be released Thursday.

“If the pressures continue to build even after we take these measures, we’ll come back and take additional measures,” Bedford warned.

Delays have already been prevalent at airports nationwide, with instances of extensive delays reported, particularly at Newark Liberty International Airport last weekend.

Major airlines and aviation unions have been advocating for Congress to end the shutdown to alleviate staffing issues. Aviation analytics firm Cirium noted a broader slowdown in the aviation system related to staffing disruptions, especially after controllers missed their first full paychecks. Despite the challenges, many controllers have continued to work mandatory overtime, leaving little time for side jobs to cover living expenses. Continued government shutdowns could lead to chaos in the skies if air traffic controllers are disrupted further.